becasue the retard that designed it wanted it to be
There are 7 periods in the modern periodic table.
The rows in the periodic table are called periods. There are 7 periods in periodic table.
rows. the vertical columns are called periods
The horizontal rows are periods on periodic table. There are 7 horizontal rows in modern periodic table.
The periodic table has 7 rows and 32 columns.
The horizontal rows on the periodic table are called periods.
The rows are used to study the change in trends. There are 7 periods in periodic table.
Horizontal rows on the Periodic Table of Chemical Elements are called periods.
Horizontal rows are called groups. Groups are formed according to the atomic number.
They are the horizontal rows in the periodic table
The rows are also called periods.
The horizontal rows on the Periodic Table are called periods.